PHYTOCHEMICAL AND IN VITRO ANTIMICROBIAL EVALUATION OF ETHANOLIC EXTRACTS OF PROSOPIS JULIFLORA (SW.) DC (FABACEAE)

Abstract

Prosopis juliflora, a multipurpose dry land tree or shrub introduced to Kenya due to concern about desertification, deforestation and fuelwood shortages, has become invasive, forming dense, impenetrable thickets, associated with unfavorable impacts on human economic activities. It has soothing, astringent, antifungal and antiseptic properties and is commonly used to treat eye conditions, open wounds and dermatological ailments. An assessment of phytochemical composition and antimicrobial activity of ethanolic extract of root(REE) and leaves(LEE) of P. juliflora against clinical isolates of Candida albicans, Staphylococcus aureus(ATCC-25923), Bacillus subtilis , Escherichia coli (ATCC-25922) and Pseudomonas aeruginosa (ATCC-27853) was carried out using paper disc diffusion method. The results of investigation showed that all the extracts had inhibitory effect on the growth of all the isolates. Only chloramphenical, erythromycin and minocycline were effective against all the bacterial strains tested and there was no significant difference (P > 0.05) between the activity of REE and LEE at the highest concentration compared to the activity of chloramphenical, erythromycin and minocycline. S. aureus showed the lowest susceptibility to most of the conventional drugs while B. subtilis was most susceptible to chloramphenical. All the bacterial strains exhibited susceptibility to erythromycin and minocycline while Penicillin, methicillin and ampicillin were the least effective antibiotics. Both LEE and REE exhibited better antifungal activity compared to cotrimoxazole and all the extracts had saponins, tannins and alkaloids; phytochemicals whose antimicrobial properties are well documented. Results from this study strongly validate use of P. juliflora in the management of microbial infections.